This invention pertains to a method and apparatus for facilitating the operation of railway trains. More specifically, the invention comprises a novel method and apparatus for dynamically monitoring car presence upon an underlying track profile and calculating car coupler forces throughout the extent of a train to provide an informational base for optimizing operation of the train over a predetermined route of travel.
In the infant stages of railroad technology locomotive pulling capabilities limited the length of trains to a few cars, such as 10 to 20, with corresponding relatively low maximum speeds on the order of 20 to 30 miles an hour. During this era even novice locomotive enginemen had little difficulty in controlling a train. In this connection the entire train could be effectively monitored merely by rearward observation from the locomotive cab. Efficiency around curves and on grades, as tempered by safe operational procedure, could be quickly acquired by a "seat of the pants" feel since the entire train essentially acted as a single unit wherein grade and curvature effects produced upon the locomotive were in essence concomitantly applied to the entire, relatively short, train.
Over the years, however, advances in railway engineering, such as the development of diesel electric locomotives utilized in multiple unit consists have advanced pulling capacities several magnitudes with respect to the early wood burning steam drive systems. This increase in pulling capacity has permitted marshaling longer and longer trains with higher and higher tonnage. It is no longer uncommon to encounter train consists of one hundred and fifty to two hundred cars stretching over a length of one, one and one-half to two miles.
In addition to the foregoing increases in train length and tonnage, a desire for increased operating efficiency has pushed operating speeds upward.
Unfortunately, with the foregoing noted increase in train lengths, tonnage and operating speeds, locomotive operational control equipment has remained substantially unchanged. In this connection enginemen still are operating trains to a large extent based upon a "seat of the pants" feel.
While experience and feel for train operational forces have remained the standard of the industry, efficiency can only be acquired after many years of experience over a well known run. In this regard it will readily be appreciated that human sensory perceptions as to grades, curves, etc. within a locomotive have little relevance to the end of a train one or two miles away. Further, gentle grades are often imperceptible to an engineman, although with long train lengths, high tonnage and elevated speeds, significant coupling forces may be produced between adjacent cars even on gentle grades.
It would therefore be highly desirable to provide a method and apparatus which would present a locomotive engineer or engineman with an accurate appreciation of track profile and relative train presence throughout the extent of the train, as the train proceeds along a predetermined route of travel. With this basic information available, it should be possible for even a relatively novice engineman, totally unfamiliar with the terrain of a particular run, to efficiently utilize grades to maintain optimum speeds and slack conditions as the train proceeds along the route of travel.
The above noted control difficulties are greatly accentuated when dynamic "train action" forces are considered. In this regard, train action or slack action events may be defined as a phenomenon which occurs as a consequence of the existence of slack in couplings between moving railway units. Such slack enables the units, during system travel, to undergo relative movement. Thus, train action denotes the equalization of speed of adjacent units which have undergone relative movement. A train action event is termed a "run-out" where adjacent units are moving apart. Where adjacent units are converging, the train action event is termed a "run-in".
There are numerous undesirable aspects associated with train action phenomena. During train action events shock forces are transmitted through the coupling units. These shock forces are propagated in a more or less wave form throughout the train. Such train action induced shocks are frequently severe enough to both damage goods carried by the trains and cause injury to train crewmen. Indeed train action induced forces may be severe enough to induce car partings and in some circumstances even derailment.
In the recent past, significant advances have been achieved in terms of obviating or minimizing the severity of slack action forces by the development of hydraulic cushioning units operable to be connected in series with car coupler shanks. Examples of such hydraulic cushioning units are disclosed in Seay U.S. Pat. No. 3,301,410, Blake U.S. Pat. No. 3,463,328, Seay U.S. Pat. No. 3,589,527, and Stephenson U.S. Pat. No. 3,589,528, all assigned to the assignee of the subject invention.
Notwithstanding, however, singular advances provided the railway industry by the development of hydraulic cushioning units, room for significant improvement remains in dealing with train action events.
In this latter connection it would be highly desirable to provide a method and apparatus for dynamically determining coupling forces throughout a train of widely varying consist as the train proceeds along a predetermined route of travel. With such force profile data an engineman may anticipate train action events so that appropriate preventive locomotive control may be initiated through appropriate application of the locomotive throttle, locomotive dynamic brakes, locomotive independent air brakes and/or automatic train brakes.